Tracing a bullet through sound waves

[abhkr]

Physics is just awesome and always interesting.

[gimmeraindays]

Great explanation, you can kind of hear it as a boom-clap

[Tux-wv]

Physics is mind blowing thank you for sharing this with us

[mateusmorgado]

That's how you recognise an American scientist. Meters ❤

[GruntUK]

But rifle rounds can vary as much as 1000fps in velocity, identifying the round used is critical.

[salvadormuro]

Who figured that out 🤯 That’s nucking futs

[leolion]

Huh so like thunder when you count to approximate the distance

[tingle]

This is really interesting and cool, but also it was very clear where the shooter was, because so many people saw him on the roof with a rifle lmao

[cactusbaboon]

Ok, good for sonic, but what about sub-sonic bullets? No sound-barrier shockwave ahead of the muzzle blast wave.

[LTLoudpack]

I don't know the specifics of the gun the shooter used. But it's reasonable to assume that it was a fairly standard 16" AR shooting 55gr ball ammo.

I've been shot at before as a personal experiment. The gun used had a 14.5 barrel with a SI Miller Comp (basically a 3 port muzzle break). And we shot 62gr M855 from about 100m-110m.

A 16" Barrel with 55gr bullets usually run at 2900 FPS, though I've seen over 3000 before. My 14.5 running 62gr Ammo shot an average of about 2870 FPS.

There's probably a lot of factors that aren't accounted for, such as altitude from sea level, microphone VS my naked ear, etc. But when I first saw the video of Trump getting shot at I came to the conclusion that the shooter was about 100m-110m away. Come to find out I wasn't too far off the mark.

[zumabbar]

how the schlieren imaging is performed would be an interesting topic for another shorts!

[kantetoast]

How you know the speed? Loads vary, the barrel lenght is unknown and the decelerarion depending on the bullets shape, air temperature, humidity. On the one hand it only seem usefull for a interesting math test for school. On the other hand you can pin down, the dead from the roof is really the shooter and not someone far more away.

[patrickgronemeyer]

Completely unnecessary... The experts could have just used Google maps and banked on the fact that the alphabet agencies would fail to do the most basic aspect of their job...

[TurtleButTrans]

God damn why couldnt they have been an inch to the right

[kendalc]

Wouldn't the bullet speed up and slow down gradually. And at point what point do sound waves fizzle out